camlistored: use osutil for default TLS cert/key

http://camlistore.org/issue/254

Change-Id: I9a0944497db64387058230c5245ed2718f36fde2
third_party/mgo: updated to rev 253

Change-Id: I995db6e123b1ef3d6061774aa333c7dbe645a744
Merge "third_party/mgo: updated to rev 253"
sorted/mongo: close iter now that we have recent mgo

Change-Id: If8e7f2ba611f2d3704acece56e03804bf9bd44f7
Merge branch 'master' of https://camlistore.googlesource.com/camlistore